Schedule 40 & 80 Conduit FAQs

I need to bake a section of your ETL listed nonmetallic conduit in the oven (for a non-electrical application). Is it OK if I bake it at 275 degrees for say an hour or will it melt?

Our Schedule 40 and Schedule 80 Conduit has a maximum ambient temperature of 122 deg. F. It will melt at 275 deg and therefore, we would advise against baking it.

A customer is questioning the use of schedule 40 PVC conduits through a roof. They are concerned with the conduit melting at the point it penetrates the roof due to heating by the sun. At what temperature would the surface of the roof need to reach to cause this?

Article 352(D) of the National Electrical Code states that it has a maximum ambient temperature of 122 deg. F. We have known PVC conduit to be used in many on the roof applications. The biggest worry there has been the use of expansion joints.

A question of the strength of a glued elbow, in particular on 3" Schedule 40 PVC; how many pounds of force are needed to separate a joint? Will the joint just pull apart or break?

A properly solvent cemented joint will become the strongest part of a conduit assembly and can withstand direct pulls in excess of 1000 pounds per foot. We have seen failures, as breakage, during testing that occurred with the conduit. In the field it is common to see couplings pull apart or pull out of boxes by breaking their locknuts. This is usually caused by the contraction of the conduit do to temperature changes and the lack of expansion fittings.

A state inspector in LA has told an inspector that he cannot use PVC in the slab of the hospital in patient care areas. Is he going to have to rewire overhead?

Refer to NED 517.13(A), all branch circuits serving patient care areas shall be installed in a metal raceway so that a redundant ground path is present (ground wire plus the metal raceway). Nonmetallic raceways, exposed, or concealed or encased in concrete are not permitted for branch wiring when installed in patient care areas.

All the medium voltage cable we sell is rated mv105, as is much of the secondary 600volt wire as well. The engineer on a current project is worried about installing mv105 cable in 90deg duct. What is your view on this?

I unaware of any nonmetallic PVC Conduits that are listed and marked for conductors or cables rated higher than 90 deg C. The National Electrical Code Section 352.12(I) reads as follows:

"(I) Insulation Temperature Limitations.  Conductors or cables rated at a temperature higher than the listed temperaturerating of the PVC conduit shall be permitted to be installed in PVC conduit, provided the conductors or cables are not operated at a tmperature higher than the listed temperature rating of the PVC conduit."

One example of an application for this exception is the use of 105°C rated medium voltage cables, Type MV, where the cable ampacity at the 105°C rating is reduced to the cable ampacity at 75°C or 90°C and, thus, matches the listed operating temperature rating of the nonmetallic conduit (75°C or 90°C.)

Always refer to the latest edition of the NEC to validate these answers.

Assuming a straight 10' length of schedule 80 conduit how much flexure is acceptable or can safely be obtained without kinking the conduit? If one end is at zero and fixed how much bend can I put in the piece? How many inches off would the other end be?

We are not sure. PVC Conduit does not kink because of its yield strength. Instead it will break when over bent. Also, it is possible to take 60 feet of conduit and make a 90 degree bend without the use of heat. This is know as cold field bending. Refer to NEMA TCB-2 for additional information on cold field bending. All PVC conduit is required to be supported when exposed per Section 352.30 of the National Electrical Code.

Can I put a 10-3 UF-B and 10-2 UF-B set of cables in your ¾” Schedule 40 rigid conduit? The run will be about 170’.

Please refer to Chapter 9 of the National Electrical Code. Note 9 of Table 1 states that cables are to be treated as a single conductor for calculating the wirefill. The major diameter of the cable shall be used in your calculations. If you are pulling both cables into the conduit then you are permitted a 31% fill. If it will be a single cable then 53% is to be used.

Can PVC SCH 40 penetrate a two-hour (concrete block) wall? If so, can you supply fire code information?

PVC Schedule 40 can penetrate a 2 hour concrete block wall. The proper fire stopping material must be used.

Can Sch 40 be run vertical in a building between floors?

Yes, Schedule 40 is permitted to run vertical between floors. If the floor is fire rated than a Certified Fire Stop will have to be used at the penetration.

Can Sch 40 Electrical Conduits be used in interior building environments? Can Sch 40 Electrical Conduits be located in Return Air Plenums? Same questionregarding warehouses & industrial interior environments?

Yes, ETL listed Schedule 40 PVC can be used in interior building environments, warehouses, & industrial interior environments. In fact, it can even be used behind or can penetrate fire-rated walls, provided a firestop is used. Article 352 of the National Electrical Code governs the use of Schedule 40 and 80 PVC Conduit in aboveground (interior or exterior), direct burial, or concrete encasement applications. No, PVC cannot be used in air handling plenums.

Can you tell me where to find a spec on PVC that talks about the ASTM? He mentioned something about D1785.

ASTM D-1784 would be the correct reference for Schedule 40/80 PVC electrical conduit, not D1785.

Do you have anything in writing that would state the fire rating of Schedule 40 conduit?

Schedule 40 PVC Conduit does not have a fire-rating but can be used in fire-rated construction.

Do you have or know of a conduit fill calculator for innerduct, both EMT and PVC?

For electrical applications, the National Electrical Code offers wirefill tables in Chapter 9. 

Do you have or know of a conduit that has an ID between 0.950 and 0.975 inch? Or do you know if there is a smooth fitting that has an ID of the same size? If yes, please give model number, etc., and please give dimensions, including wall thickness.

1" Schedule 80 conduit (part number: 49408) has any average inside diameter of 0.957". Outside diameter = 1.315" Wall thickness = 0.179". Conduit is an OD controlled product while the ID has the largest tolerances. The minimum ID permitted for 1" schedule 80 conduits is 0.910".

There are no smooth fittings with that ID.

Do you make 4" Schedule 40, 20' in “white”?

No, our standard product is gray. Plumbing Schedule 40 usually comes in white.

Do you make flexible Schedule 40 PVC for use with your rigid schedule 40 PVC ? We are trying to bid an electrical substation project for a utility that calls for flexible schedule 40 PVC. 600V ductbanks for low voltage power and control ckts.

Schedule 40 is a dimensional requirement for Rigid Nonmetallic Conduit. There is no such thing as flexible PVC Schedule 40 conduit.

Do you make your schedule 80 PVC in 3-1/2"?

No we do not. 3" or 4" Schedule 80 PVC is available.

Do you manufacture 8” EPC40 (Sch 40) PVC conduit and if so what are its dimensions?

8" Schedule 40 Conduit is a non-listed conduit for utilities and meets NEMA TC-2. Prime Conduit's part number is 59618 and is available in either 10 foot or 20 foot lengths. It has an outside diameter of 8.625" and an inside diameter of 7.981". The bell depth is 6.375".  Refer to our catalog for additional information.

Do you manufacture metric size conduits?

We do not manufacture metric size conduits. We only manufacture electrical conduits made from PVC to UL651 and NEMA TC2.

Do you offer a plenum rated rigid PVC conduit?


Do your schedule 40 and 80 electrical conduit PVC products have the same outside diameter? This would allow me to put Sch. 80 under my driveway and then switch to Sch. 40 in areas of less stress?

Yes, Schedule 40 and Schedule 80 do have the same outer diameter. They differ in wall thickness and inside diameter, so please take into account that less wires will fit into the Schedule 80.

Have you heard of "High Temperature, Thick Wall" PVC? I asked how high temperature and they said 200 degrees.

No, especially since PVC has a generic relative thermal index of around 140 deg F, and the maximum ambient temperature per the National Electrical Code is 122 deg. F unless tested to a higher temperature. I would imagine that PVC would not able to retain its form at 200 degrees since this is the temperature that conduit benders are heated to.

How can you tell if Schedule 40 PVC pipe has been recycled?

How do you mean, "Recycled"? Like taken from an old installation to a new installation? We have print codes on our conduit that can tell us when it was made. Conduit does not sit in our yards for a long time.  In addition, conduit needs to be solvent cemented together at the joints. Have all the integral bells been cut off? This would be an easy way to tell the conduit is being reused. If you have any elbows in question look for wear on the inside wall due to cable pulling.  I guess it is one of those things "You know it when you see it".

How long can your conduit remain exposed to direct sunlight before it becomes damaged, brittle, and unable to protect the service?

Our listed Schedule 40 and 80 PVC Conduit has been evaluated for sunlight exposure by ETL per UL651 and in accordance to Section 352.  The PVC Conduit utilizes UV inhibitors and has an indefinite life when used in exposed applications where direct sunlight is present.

How many sticks of 4", 3", and 2" Sch.40 PVC come in a bundle when being delivered?

4" will have 57 sticks, 3" - 88 sticks and 2"- 140 sticks.

How much air pressure will 1 in. Schedule 80 take?

Only pressure rated PVC tubing can be used for air pressure applications. Prime Conduit's Schedule 80 PVC Conduit is a listed raceway for electrical conductors and cables.

We do not make pressure rated tubings.

I am going to bury conduit 24" below the surface of a rock driveway. There will be 250' long semi trucks and trailers driving along this driveway. What do you think about using Sch 40 or 80? What is recommended?

I would recommend that you look at our external load calculation document.

External Load Calculations for Direct Buried Conduit

I am interested in using corrugated HDPE. How many 1.5" I.D. innerducts can be placed in a 4" Schedule 80 PVC conduit?

It is dependant on several factors like length of run, OD of innerducts, number of bends, and so forth. Our best conservative estimate is that only one 1-1/2 innerduct would fit comfortably in this outerduct. Typically, two to three of the 1-1/4" innerducts or four 1" innerducts will fit in 4" Sch 80, however; again this is dependant on several factors.

am working on a project that has exposed conduit subject to winter temperatures as low as -20 degF and summer temperatures of 110 deg F. My questions relates to the cold weather application. Is there a temperature that PVC conduit is not recommended? Does the PVC loose some of its durability for exposed applications under lower temperatures? Is installation a problem under temperature extremes?

PVC conduit does not have a low temperature limit. When PVC is exposed to very low temperatures it will become more brittle. This is only a problem when it gets impacted. Since Schedule 40 PVC conduit is not allowed to be use in areas of physical damage (Section 352)  this should not be a problem.

Schedule 80 PVC Conduit is listed for uses in areas of physical damage and has been used in impact areas of low temperatures throughout the years without a problem. We always recommend erring on the side of safety. If you believe that low temperatures and areas of impact are going to be a problem use a metal conduit. I rather you call me and tell me you did not use our product, than call me with a failure.

I couldn't find any information on 8" P&C Duct Type EB or DB in your on-line information. Do you still make 8"?

The only 8" duct that we offer is the 8" Schedule 40 non-listed conduit in 10 or 20 ft lengths. Part numbers are 59618 followed by -010 for a 10 ft length or -020 for a 20 ft length. Furthermore, this can be concrete encased.

I have a contractor who needs to know about disposing of Schedule 40 pipe. Does it go in the recyclable or to a land fill?

It can go either. Since the PVC will not decompose it is not ideal for landfills. It however will not cause any damage to drinking water. Since PVC is a recyclable material it should be recycled whenever possible. There should be a local PVC recycling center near your contractor.

I have a contractor who would like to know if primer must be used when connecting Sch40 PVC. In other words, will PVC cement work without the primer and is it considered to be installed correctly without the primer?

The National Electric Code does not require primer to be used in addition to PVC solvent cement. However, primer will aid the assembly and ensure the quality of the joint, as it better prepares the joint for solvent cementing.

Contact your solvent cement and primer manufacturer for additional information.

I have a customer looking for some kind of spec that states what the Fire rating as well as the Fire Spread rating is on Schedule 40.

PVC conduit is not fire rated like an outlet box would be. When conduit penetrates a fire wall assembly the fire stop that is used is classified for the conduits it can be used with. Listed PVC Conduit is "Flame Retardant" per Section 352.100 of the NEC. The flame testing is found in the product standard UL651. Our product is ETL listed to UL651. Listed PVC conduit is not capable of conveying a flame. PVC is a self-extinguishing material that does drop flaming particles.

I have a customer that is under the impression that schedule 40 PVC conduit installed underground should never have water in it. It has always been my impression that PVC conduit installed underground is not a 100% watertight installation nor is it meant to be.

All conduits and ducts, whether they are nonmetallic or metal, will get moisture in them. The moisture gets in through leaky joints or condensation. That is why the National Electrical Code started to require that all conductors or cables be listed for a "Wet Location".  See section 300.5 of the NEC.

I have a customer who needs the burst strength for SCH 40 standard couplers 1" through 4”. Can you help me with this?

We don' t have a burst strength. Our conduit is not intended for internal water or air pressure, such as water pipe would be; therefore we are not worried about it bursting.

I have an application for underground conduit in an area of geothermal activity. The design temperature for the ground surrounding the conduits is 69 degrees C. What is the ambient temperature rating of your PVC conduits?

Per Article 352(D) of the National Electrical Code, our PVC conduit has a maximum ambient temperature of 50 deg. C or 122 deg F. When concrete encased, it has been able to withstand temperatures up to 150 deg. F. Beyond that, you will begin to experience deformation, etc. We would not recommend our PVC conduit for your application.

I have an existing Sch 80 pipe installed and they are connecting Sch 40 pipe to the Sch 80. Because of the different I.D. there is a small lip where the two connect. Is there an adaptor to make the uneven surface less uneven?

No, they will just have to ream the conduit to account for the step between the conduit sizes.

I have been tasked with designing a piping run for a customer. The product that is to be transported is 25% solution of sodium hydroxide. The customer wants to use D.I.P., and I am trying to convince them to use PVC. Would you please send me some information on the corrosion properties of PVC. concerning sodium hydroxide?

We can not recommend our conduit for applications other than what it is intended for: electrical, telecommunications, or utility applications. You are correct in the fact that PVC is corrosion resistant against many chemicals. If you go to the following website, you can find the chemical resistance for PVC. Choose PVC for the material and it will tell you how chemicals react to it.

I have not been able to find any information on recommended or allowable minimum radius bends for cold bending of conduit to incorporate minor changes in direction. I do have an old catalog (1981) that has a list for minimum radius bends for P&C Duct but no info on Schedule 40 Duct.

The minimum-bending radius for schedule 40 conduits is found in Table 2, Chapter 9 of the NEC.  Also refer to Article 352 of the NEC for bend information. Of course these numbers were for hot bending (the numbers you got before for P&C Duct were to0.)

I install walk-in cold boxes and freezers. I use PVC conduit and fittings in these installations. I have been able to find the highest temperature that your product can be exposed to but not the lowest temperature. I have rooms that are operating at -20 deg. C. (approximately -4 deg F). I need some type of documentation stating the highest and lowest temperatures that your PVC conduit and fittings can be exposed to.

Schedule 40 does not have a lower temperature limitation since it is not allowed to be used in areas where subject to physical damage. Care and common sense must be considered in these applications. PVC material does not breakdown due to lower temperatures, but will become more brittle and therefore more susceptible to damage due to physical contact. PVC conduit has been used in many freezer applications.

I just had an individual call and they are redoing an old home and want to use Sch 40 PVC in the walls. They will be removing the siding on the outside of the home and rewiring running romex thru the conduit. They would like to use PVC instead of metal conduit. Is this an approved application?

PVC Schedule 40 is approved to be used indoors. It can be used behind wall or on the surface of the wall (provided it's not subject to physical damage). If it penetrates a fire wall, it has to be firestopped. Article 352 of the National Electrical Code governs the use of PVC conduit.

I know PVC conduit is not acceptable for use in Hazardous Areas, but a question has come up regarding the use of PVC conduit underground in a tank farm. Will crude oil degrade the integrity of PVC conduit?

PVC is resistant to crude oil and will not degrade when exposed to it.

I need to know how cold the rigid nonmetallic conduit and accessories can operate. We are looking to use this pipe outdoors in a location that could reach -40F. What are your suggestions?

Rigid Nonmetallic Conduit does not have a lower temperature limitation; Article 352.10of the National Electrical Code states that it gets more brittle with cold temperatures. As long as it is not subject to any type of impacting, it will be fine. In fact, RNC (rigid nonmetallic conduit) has been used in many walk-in freezer applications.

I plan on installing an outlet near my swimming pool utilizing your PVC conduit. Since I'm using your conduit do I still have to use outside romex. Could I use my standard indoor romex (12-2), since it will be enclosed in conduit?

No you cannot use standard Romex in an underground raceway. Raceways installed underground are considered "Wet Location" and only cabling listed for wet location can be used. In addition, see Article 680 of the National Electrical Code for the requirements of wiring around a swimming pool.

I received a call from a local engineering firm. They are running conduit under a bridge in a high voltage application. Anyway, they are considering using either fiberglass or PVC and have asked what are the advantages to using the PVC over the fiberglass for this application.

Fiberglass is usually used in bridge crossing because they can have a larger distance between support. In addition, fiberglass is available for bullet resistance. People will shoot at the pigeons under bridges.  Besides those two facts there is not an advantage for one over the other.

I was wondering whether or not rigid PVC was suitable for a greenhouse application where the overall temperature could range from 90-120 degrees Fahrenheit. Please advise, and if so what installation methods are recommended to the contractor (i.e. expansion couplings, etc.).

Absolutely...PVC conduit has been used in lots of greenhouses. You do require expansion joints though to account for the temperature differential.

I'm working on a project and have a question regarding innderduct. We have an owner requirement to provide (2) 1.5" and (1) 1" innderduct in a 4" conduit. There is a question over whether this is physically possible.

No, the innerducts will not fit. The outside diameter of 1.5" innerduct is 1.9" and the inside diameter of 4" conduit is 3.826". Therefore two 1.5" innerducts cannot physically fit next to each other in the outerduct. Also, the same rules for wirefill of electrical conductors found in Chapter 9 of the National Electrical Code (NEC) should be followed for innerducts.

In and underground installation we are providing innerducts in PVC conduit. The question which has been raised, will (3) 1” innerducts fit into 4” schedule 80 PVC (3.826” ID)?

Yes, based on 40% of the cross section area of the 4" Schedule 80 PVC Conduit, 3.38 1" innerducts will fit. (See Table 1, Chapter 9 of the NEC for wirefill requirements).  Of course whether you can pull the product in is based on the length of the pull, number of elbows, etc. I recommend that you check out for additional information.

In reading through technical information on the website regarding temperature limitations for your schedule 40 and 80 PVC conduit, I understand the conduit is rated for use with 90 degree C conductors but it is only rated for 50 degree C ambient. If the conduit can withstand 90 degree C conductors at their full 90 degree C ampacity, why is the conduit not rated for more than a 50 degree C ambient? It seems that if the conductor temperatures are 90 degree C, the outside of the conductor insulation would be at least above 50 degree C (the conduit rating).

The ambient temperature rating is based on 10 deg. C less than the Relative Thermal Index (RTI) of the plastic. In this case, the generic RTI for PVC is 60 deg. C, so the maximum ambient temperature is 50 deg. C.

Is DB-100 PVC same as Schedule 40?

No. Schedule 40 and DB duct have the same outer diameters but differ in wall thickness. In addition, they conform to different NEMA standards. They can both be direct buried, however. We have a Schedule 40 ETL listed conduit and a non ETL listed conduit. The DB duct is not ETL or UL listed.

Is diesel fuel suitable to run through the pipe or will it break it down?

Our PVC Conduit is not designed to transport liquids nor gasses. The corrosion resistance chart is for conduit that may come into contact with these chemicals, usually externally.

Is there a problem in connecting schedule 40 and schedule 80 2" and 4" PVC conduits together in a run? Rigid steel sweeps are specified with schedule 80 PVC. The contractor mistakenly used schedule 40 under building slab. The contractor spoke to the owner and received permission to continue the conduit path with schedule 80.

No, schedule 40 and 80 can be connected with the use of couplings or their integral bell. The inside diameter of the spigot of the schedule 80 conduit should be reamed to allow a smooth transition from the 40 to the 80.

It is our experience that it is not unusual to get water seepage into underground PVC conduits. Please confirm that this is the case.

Water does not seep through the PVC itself. All conduits in underground applications get moisture in them. That is why the NEC requires conductors and cables to be listed for a wet location.

My question concerns what the standard is for sunlight resistance? We are a Florida based Electrical Contractor and a question as to how long PVC conduit can withstand direct sunlight before it will start to break down has been a topic of discussion. Summer heat and humidity is extremely harsh on everything down here and I wonder if there is a rule of thumb for determining the time that PVC will last in this environment or is this just something not to be concerned with?

UV is an issue for all plastic products. Fortunately there are additives that are added to plastics to make the material UV resistance. ETL Listed Schedule 40 and 80 PVC conduit utilizes these additives and are UV resistant. The sunlight resistance test is found in UL Standard UL651. Our product is ETL List to UL651. Listed Schedule 40 and 80 Conduit have been used in Florida for years including on rooftops. It is preferred along the coast because it is corrosion resistant. When used in an exposed environment where there are changes in temperatures please are sure to use enough expansion fittings.

Please advise if you have any installation instructions for bending PVC in the field. We are intending to use the Greenlee PVC heater sand will be bending sizes 2-6". We would like the contractor to follow the manufacturers suggested procedures. I was searching your site but was unable to locate any information.

PVC conduit manufacturers recommendation are to follow the procedure provided by the manufacturer of the PVC bending equipment, in this case Greenlee.

Under what conditions would Sch. 40 or 80 RNC be suitable per mfg instructions as a support for cable that is ran on the outside of the installation and tie wrapped to the conduit. For example does Prime Conduit's listing instructions allow a No. 4 copper conductor attached to the exterior for it’s length to be in compliance with the provisions of Article 300.11 (B) of the NEC?

Schedule 40 and 80 PVC Conduit is not identified in its listing as a means of support for other raceways, cables or conductors as described in 300.11(B). Therefore the No 4 copper conductor is not permitted to be supported by the raceway on the exterior of the product.

We are in the process of bidding a project and they are requiring PVC conduit for the medium voltage to be 105 C. Does Prime Conduit manufacture 105 C schedule 40 PVC conduits?

We do not.

Please recognize that most wire and cable manufacturers no longer mark Type MV conductors or cables for 90 degrees C since the conductors meet the 105 degree C requirements and are marked for the higher temperature rating. The code currently prohibits the installation of the 105 Type MV conductors and cables since they are rated higher than the RNC temperature rating. The temperature rating of the conduit will not be exceeded since the users do not operative MV conductors or cables above 90 degrees C. The rated temperature is based upon the rating of the insulation and jacketing material used in the construction of the cable, not the operational temperature.

We are looking at a swimming pools pump room project that requires wiring in an environment that contains muriatic acid. I did look at your corrosion resistance table but did not see muriatic acid listed. Is your PVC conduit listed for this environment?

Muriate Acid also know as Hydrochloric Acid (HCL) is unacceptable for PVC raceways when it is at 100% concentrations. PVC conduit is good to use at concentrations of 37% or less.

We disagree as to whether the inside of rigid nonmetallic conduit is considered a wet location when installed underground or in a slab or concrete in direct contact with the earth. What is your understanding of this?

All conduits (raceways), whether they are metal or nonmetallic, installed in underground locations are considered a wet location. In fact, the National Electrical Code has adopted language for Section 300.5(B) to say: "Insulated conductors and cables installed in these enclosures or raceways in underground installations shall be listed for use in wet locations and shall comply with 310.10(c)"  Moisture can enter the raceway because of leaky joints and/or due to condensation that occurs to the heating and cooling of the conductors.

We have a contractor who is using Sch 40 conduit inside of a cinder block wall as a sleeve for MC Cable. The wall is a 2 hour fire rated wall and the inspector is saying PVC can not be used inside the fire rated wall. My understanding is it can be used inside the wall and the only issue is where there are penetrations and at that point we need to firestop.

Schedule 40 is permitted to be used in fire-rated walls. If it penetrates a fire rated wall, a fire-stop must be used.

What is the burn time for the n/m conduit. Is it two hours or less?

RNC PVC Schedule 40 does not have a "burns time". The product has been evaluated and approved for use within a two-hour firewall assembly. Some would say the product has a "two hour rating".

What is the dielectric strength and what are the RF loss factors for Schedule 40 and Schedule 80 Rigid PVC Conduit? How much voltage at 1 megacycle (1 MHz) can the conduit withstand on a long-term basis between a 7/8"conductor inside the conduit (1.5 inch) and a sheet metal edge 1" from the conduit on the outside?

The dielectric strength of PVC per ASTM D149 is 1100 volt/mil. I am unaware of the "RF loss factors". We are also prohibited to perform any design calculations (nor would I know where to begin).

Please contact the Vinyl Institute for assistance and also you may want to contact the conductor manufacturer for additional information.

What is the difference between your standard Schedule 40 and the Heavy Wall Rigid Schedule 40 Utility Conduit?

Standard Schedule 40 is ETL listed, while the Utility Schedule 40 conduit is not. Also, Schedule 40 can be used aboveground, whereas the utility Schedule 40 cannot.

What is the ignition temperature of PVC conduit when tested in accord with Unified Building Code test procedure 26-6? What is the Smoke Density Rating of PVC conduit when tested in accord with Unified Building Code test procedure 26-5? What is the smoke Density Rating of PVC conduit when tested in accord with Unified Building Code test procedure 8-1?

Conduit has been evaluated to be use in buildings. PVC cannot be used in air handling plenum.

What is the Intertek / ETL mark?

Prime Conduit is pleased to announce the addition of Intertek/ETL to our family of Nationally Recognized Testing Laboratories (NRTLs). You will now see the ETL Listing mark on our conduit and elbows. Prime Conduit customers are accustomed to seeing the UL listing mark and CSA certification mark on our many products. At this time, we would like to introduce the ETL mark to our Schedule 40, Schedule 80, and EB 20 Conduit and Elbow product lines. Nearly every installation falls under the jurisdiction of some regulatory agency. Most of the electrical installations are regulated by state, local and national installation codes. The most commonly used Regulations are found in the National Electrical Code (NEC). Rigid PVC conduit and elbows are covered by Section 352.6 states “Listing Requirements. PVC conduit, factory elbows, and associated fittings shall be listed.” Listing can be provided by any OSHA approved NRTL. A Nationally Recognized Testing Laboratory (NRTL) is an independent laboratory recognized by the Occupational Safety and Health Administration (OSHA) to test products to the specifications of applicable product safety standards – such as those from Underwriters Laboratories (UL), CSA, NSF and other standards – writing bodies. A NRTL’s function is to provide an independent evaluation, testing and certification of any electrically operated product. For more information regarding Nationally Recognized Testing Laboratories go to:

What is the maximum number of 3/4"innerducts I can get in a 4" pipe?

Using 4" Schedule 40 Conduit with a ID of 4.026" and a Innerduct with an OD of 1.050" we determined 8 innerducts would fit. The actual number that will fit will vary depending on the number of elbows, length, etc.

What is the minimum bending radius for all sizes of your schedule 40 Rigid Nonmetallic Conduit?

Please refer to Chapter 9, Table 2 for radius of conduit and tubing bends.  This is also found in UL651 for schedule 40 and 80 PVC conduits.

Would like to know if you have any technical info on installations where waterproofing the ducts is necessary. This particular installation has ducts buried below the water table and would normally be submerged. If expansion joints are installed, are they water tight?

Conduit is designed for wet locations as is evidenced when it is in direct burial or concrete encasement applications. Furthermore, the expansion fittings have two o-rings and they are suitable for wet locations. However, in most direct burial or concrete applications, expansion fittings are not required as they take on the expansion/contraction rate of the earth or concrete and thus become ineffective.

Would you please advise whether SCH 40 PVC conduit is suitable for submerged watertight application? Does conduit have a rating such as NEMA 6P, or IP68? We arereviewing the suitability of using SCH40 PVC conduit to connect to a submerged measuring device, which has an IP68 rating.

Schedule 40 conduit does not have a 6P rating or an IP68 rating. It is listed for wet locations.

Do you have any pipe stiffness data for your Schedule 40 and 80 Conduit?

Unfortunately Prime Conduit does not have listed PSI ratings for our Schedule 40/80 ETL listed PVC Conduit.  Our Sch 40/80 ETL listed conduit meets NEMA TC2 and UL651 requirements, in regards to crush testing requirements.  Furthermore, our products do not have an internal PSI rating as they are not intended for transfer of any fluids or gases.

What is the crush rating of Schedule 80 conduit?

The crush rating is listed in UL651.  Our ETL listed Sch 80 meets the crush requirements of section 6.9 and table 6.3 per the UL651 standard.  For sizes 1/2" - 6" it shall not deflect more that 30% at a load of 2000lbs/force.

What is the crush rating for your Schedule 40 conduit?

The crush rating is listed in UL651.  Our ETL Listed Sch 40 conduit meets the crush requirements of section 6.9 and table 6.3 per the UL651 standard. 

It shall not deflect more that 30% at the following lbs/force loads:

Trade Size

Schedule 40


1000 lbf


1000 lbf


1000 lbf


1000 lbf


750 lbf


700 lbf


1000 lbf


1000 lbf


1000 lbf


900 lbf


850 lbf


850 lbf

What is conduit's Schedule B code?

Per the 2013 Schedule B Book, PVC conduit is 3917230000 (TUBES, PIPES & HOSES, RIGID, OF POLYMERS OF VINYL CHLORIDE)

39.17 - Tubes, pipes and hoses, and fittings therefor (for example, joints, elbows, flanges), of plastics:

3917.23.0000 - - - Of polymers of vinyl chloride

Click on the following link to search the latest information:

What is your conduit's ECCN number?

ECCN, stands for Export Control Classification Number. An ECCN is an alpha-numeric classification used in the Commerce Control List to identify items for export control purposes. An ECCN is different from a Schedule B number, which is used by the Bureau of Census to collect trade statistics. It is also different from the Harmonized Tariff System Nomenclature, which is used to determine import duties.

A Customer Service Rep. told Prime Conduit that conduit's ECCN number falls in the "catch all" category of EAR99.

Click on the following link for additional information regarding ECCN numbers:


Where can I find an MSDS for Conduit and Fittings?

MSDS are not provided for conduit, elbows, or fittings, etc. because those products are an "article" under the OSHA Hazard Communication Standard (HSC), 29 CFR 1910.1200.


The Hazard Communication Standard has an exemption for articles.  To fall under the article exemption, the product must be a manufactured item:  (1) which is formed to a specific shape or design during manufacture; (2) which has end-use functions dependent in whole or in part on its shape or design; and (3) which does not release, or otherwise result in exposure to, a hazardous chemical under normal conditions of use.  The PVC conduit, elbows, or fittings, etc. produced by Prime Conduit meet all of these criteria and, consequently, are exempt from the Hazard Communication Standard.


Please refer to the following web page for more information:

Rodent attack on PVC conduit or duct

We are often questioned on the possibility of a rodent (groundhog, rat, etc...) Chewing through direct buried or exposed pvc conduit and duct.  We have responded to these questions by assuring our customers that pvc conduit or duct is not a source of nutrition,  therefore is not subject to the attack of rodents.

 The National Sanitation Foundation (NSF) conducted a series of tests designed to determine the susceptibility of PVC sewer pipe to attack by rodents.  [1]  PVC pipe was cut into sections and were installed in the openings of a rat enclosure as a barrier between the rats and sources of food and water.  The rats were supplied with reduced rations of food calculated to maintain good health but constant hunger.  After one month period of testing the pvc pipe sections showed evidence of the rats attempts to gnaw through to obtain the additional food,  but there was no penetration of the pipe.  There is no evidence of an attempted attack on the pipe when it did not interfere with access to food.

 It should also be noted that rodents will chew on anything to keep their teeth sharp and to control the length of the teeth.


What ASTM test does your conduit meet?

Prime Conduit's conduit meets several different ASTM tests.  However, the primary one that is most referenced is ASTM D 1784.  Our conduit is ETL Listed to UL651.  UL651 states “The compound of which rigid PVC conduit and fittings are made shall be as described in Standard Specifications for Rigid Poly(Vinyl Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride)  (CPVC) Compounds, ASTM D 1784.”  Therefore, because it is ETL Listed to UL651, it meets ASTM D 1784.

ASTM 1784 - Standard Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride) (CPVC) Compounds

What is the PVC content in conduit?

These are all estimations:

Most molded fittings and boxes are going to be 85% to 87% PVC

Some small diameter may be as high as 85%, but the majority of 2" and smaller is around 81%

Schedule 80 products will also be around 81% PVC

Larger schedule 40 will be close to 69%

Non UL EB/DB products are as low as 59% PVC